Data transmission method for embedded data, data transmitting and reproducing apparatuses and information recording medium therefor

ABSTRACT

In a data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps:  
     adding error correction codes for correcting error to said additional information data;  
     embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and  
     transmitting the information data embedded with the repetitive additional information data therein, and comprising, at a receiver side, following steps:  
     receiving the transmitted information data embedded with the repetitive additional information data therein;  
     detecting the repetitive additional information data embedded from said transmitted information data received;  
     determining said additional information data on a basis of a majority rule when receiving said information data; and  
     correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a data transmission method fortransmitting and receiving data, such as video and/or audio data inwhich additional information data (i.e., data hiding or water mark,etc.) are embedded or concealed, and apparatuses for transmitting andreproducing such the video and/or audio data, and in particular, relatesto data transmitting and reproducing apparatuses for embedding anddetecting the additional information data which are embedded orconcealed into the data being transmitted, as well as an informationrecording medium therefor.

[0003] 2. Description of Prior Art

[0004] Up to now, data hiding has been studied or researched as atechnology for embedding or concealing an identification informationand/or an annotation into original contents in a form of, such as textdata and/or audio/video data. In recent years, the data hidingtechnology begins to be applied as a technology for protecting a copyright from illegal operations, such as copying of the original data, byembedding such the identification information into them. Such thetechnology is described in “Data Hiding Technology for SupportingElectronic Water Mark (Upper)”, pages 149 through 162, NIKKEIELECTRONICS 1997.2.24 (no.683), by Nikkei Business Publications, Inc.

[0005] The data being embedded into the original data, however, aredeteriorated through various operations including, such as a filtering,a data compression and so on, thereby, they sometimes happen to beremoved from them, for instance, in particular, after encoding/decoding(or converting/inverting) operation thereof. Therefore, such the hiddendata are inserted or embedded in the original data or the likerepetitively, so as not to be deleted therefrom easily.

[0006] However, in the prior art mentioned in the above, there is nodescription or teaching about a concrete and/or practical way ofreproducing the additional information data which are embedded into theoriginal data repetitively, with a low error rate.

[0007] Since the video or picture data is large in an amount thereof,therefore, normally it is transferred after being compressed. Thetransferred data is then de-compressed to be restored into the originaldata, however, it is impossible to restore them back to the originalones perfectly or completely, due to the processes of such thecompression/de-compression. Further, when transmitting the data, errorsmay occur in the data depending on the route of the data transmission.For restoring such the erred data, it is ordinary to add an errorcorrection code onto it previously, and then so-called correction of theerred data can be performed therewith. However, in the restoration ofthe data with such the error correction code, though it is possible todetect the error(s) occurring in the data, it is sometimes impossible torestore or correct them if the reliability of the data itself cannot beensured at a level higher than a certain level. Therefore, it isnecessary that an error rate of the data being transmitted must bereduced as low as the error correction is possible to be applied in thelevel or degree thereof.

SUMMARY OF THE INVENTION

[0008] An object of the present invention is, therefore, for dissolvingthe problems in the above-mentioned conventional art, to provide atransmission method of such the data into which additional informationdata, including identification information data, control data and so on(hereinafter, comprehensively described by “identification informationdata”), and a data transmitting apparatus and a data reproducingapparatus, as well as an information recording medium therefor.

[0009] For achieving the above-mentioned object, in accordance with thepresent invention, first of all, there is provided a data transmissionmethod for information data containing additional information datatherewith, comprising, at a transmitter side, following steps:

[0010] a fist step for adding error correction codes for correctingerror to said additional information data;

[0011] a second step for embedding said additional information dataadded with said error correction codes into the information data byplural times, repetitively; and

[0012] a third step for transmitting the information data embedded withthe repetitive additional information data therein.

[0013] Also, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data transmission methodfor the information data transmitted through the method as defined inthe above, comprising, at a receiver side, following steps:

[0014] a fourth step for receiving the transmitted information dataembedded with the repetitive additional information data therein;

[0015] a fifth step for detecting the repetitive additional informationdata embedded from said transmitted information data received in thefourth step;

[0016] a sixth step for determining said additional information data ona basis of a majority rule when receiving said information data; and

[0017] a seventh step for correcting error with using the errorcorrection codes received and determined when said additionalinformation data contains error(s) therein.

[0018] Further, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data transmission methodfor information data containing additional information data therewith,comprising, at a transmitter side, following steps:

[0019] a fist step for encoding said additional information data inaccordance with a predetermined conversion table;

[0020] a second step for embedding said additional information dataencoded in the above step into the information data by plural times,repetitively; and

[0021] a third step for transmitting the information data embedded withthe repetitive additional encoded data therein.

[0022] Also, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data transmission methodfor the information data transmitted through the method as defined inthe above, comprising, at a receiver side, following steps:

[0023] a fourth step for receiving the transmitted information dataembedded with the repetitive additional information data encoded;

[0024] a fifth step for detecting the repetitive additional informationdata encoded, which are embedded within the information data received;

[0025] a sixth step for determining said encoded additional informationdata on a basis of a majority rule of the repetitive encoded additionalinformation data detected; and

[0026] a seventh step for decoding the encoded data into the additionalinformation data.

[0027] Further, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data transmission methodfor transmitting information data containing additional information datatherewith, comprising following steps at a transmitter side:

[0028] a step for preparing data frames of said information data intowhich the additional information data are to be embedded;

[0029] a step for altering at least part of the data frame in accordancewith predetermined patterns corresponding to the additional informationdata to be embedded, for the plural continuous frames, repetitively; and

[0030] a step for transmitting the information data embedded with therepetitive additional information data therein.

[0031] And, also, for achieving the above-mentioned object, inaccordance with the present invention, there is provided a datatransmission method for the information data transmitted through themethod as defined in the above, comprising, at a receiver side,following steps:

[0032] a step for receiving the transmitted information data embeddedwith the repetitive additional information data therein;

[0033] a step for detecting the repetitive additional information dataembedded from said transmitted information data; and

[0034] a step for determining said additional information data on abasis of continuity of the repetitive additional information datadetected for a predetermined times.

[0035] And also, for achieving the above-mentioned object, in accordancewith the present invention, there is further provided a datatransmitting apparatus for transmitting information data containingadditional information data therewith, comprising:

[0036] a first means for adding error correction codes for correctingerror to said additional information data;

[0037] a second means for embedding the additional information dataadded with the error correction codes by said first means into theinformation data by plural times, repetitively; and

[0038] a third means for transmitting the information data embedded withthe repetitive additional information data therein.

[0039] Also, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data reproducingapparatus for reproducing the transmitted information data transmittedby the data transmitting apparatus defined in the above, comprising:

[0040] a first means for receiving the transmitted information dataembedded with the repetitive additional information data therein;

[0041] a second means for detecting the additional information dataembedded from the transmitted information data received by said firstmeans;

[0042] a third means for determining said additional information data ona basis of a majority rule when receiving said information data; and

[0043] a fourth means for correcting error with using the errorcorrection codes received and determined when said additionalinformation data contains error(s) therein.

[0044] And also, for achieving the above-mentioned object, in accordancewith the present invention, there is provided a data transmissionapparatus for transmitting information data containing additionalinformation data therewith, comprising:

[0045] a fist means for encoding said additional information data inaccordance with a predetermined conversion table;

[0046] a second means for embedding said additional information dataencoded in the first means into the information data by plural times,repetitively; and

[0047] a third means for transmitting the information data embedded withthe repetitive additional encoded data therein.

[0048] Also, in accordance with the present invention, there is provideda data reproducing apparatus for reproducing the transmitted informationdata transmitted by the data transmitting apparatus defined in theabove, comprising:

[0049] a first means for receiving the transmitted information dataembedded with the repetitive additional information data encoded;

[0050] a second means for detecting the repetitive additionalinformation data encoded which are embedded within the information datareceived;

[0051] a third means for determining said encoded additional informationdata on a basis of a majority rule of the repetitive encoded additionalinformation data detected; and

[0052] a fourth means for decoding the encoded data into the additionalinformation data.

[0053] And further, according to the present invention, there isprovided a data transmission apparatus for transmitting information datacontaining additional information data therewith, comprising:

[0054] a first means for preparing data frames of said information datainto which the additional information data are embedded;

[0055] a second means for altering at least part of the data frame inaccordance with predetermined patterns corresponding to additionalinformation data to be embedded, for the plural continuous frames,repetitively; and

[0056] a third means for transmitting the information data embedded withthe repetitive additional information data therein.

[0057] Further, according to the present invention, there is provided adata reproducing apparatus for reproducing the transmitted informationdata transmitted by the data transmitting apparatus defined in theabove, comprising:

[0058] a first means for receiving the transmitted information dataembedded with the repetitive additional information data therein;

[0059] a second means for detecting the repetitive additionalinformation data embedded from said transmitted information data; and

[0060] a third means for determining said additional information data ona basis of continuity of the repetitive additional data detected for apredetermined times.

[0061] Moreover, also for achieving the above mentioned object, inaccordance with the present invention, there is also provided aninformation recording medium for recording data therein, comprising:

[0062] information data being reproducible;

[0063] additional information data which are embedded into saidinformation data repetitively; and

[0064] error correction codes which are added to said additionalinformation data and also embedded into said information datarepetitively.

BRIEF DESCRIPTION OF DRAWINGS

[0065]FIG. 1 shows an embodiment of a flow of processes ofcoding/decoding for the data transmission, in accordance with thepresent invention;

[0066]FIG. 2 shows in more details of the processes of the transmissionof the additional information data as shown in FIG. 1;

[0067]FIG. 3 shows an embodiment of a process for embedding theadditional information into the video data;

[0068]FIG. 4 shows an example of the points or positions, at which theadditional information data are embedded, within one piece of thepicture as a whole;

[0069]FIG. 5 an embodiment of a signal processing apparatus ofperforming the process of coding/decoding, for the data transmissionaccording to the present invention;

[0070]FIG. 6 shows an another variation of the flow of processes ofcoding/decoding for the data transfer, according to the presentinvention;

[0071]FIG. 7 shows further other variation of the flow of processes ofcoding/decoding for the data transfer, according to the presentinvention;

[0072]FIG. 8 shows an another embodiment of the flow of processes ofcoding/decoding for the data transfer, according to the presentinvention;

[0073]FIG. 9 shows an example of a method of deciding the identificationdata when receiving them which are embedded in accordance with themanner shown in FIG. 8; and

[0074]FIG. 10 shows an example of changes in the condition in thedecisions on the identification information data at that time.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0075] Hereinafter, various embodiments and variations of a datatransmission method and an apparatus for transmitting and reproducingoriginal data, such as the video and/or audio data, according to thepresent invention, will be fully explained by referring to the attacheddrawings.

[0076]FIG. 1 shows an embodiment of a flow of processes ofcoding/decoding for the data transmission, in accordance with thepresent invention.

[0077] In FIG. 1, there are shown an identification information bits oridentification bits, i.e., of n bits (b0, b1, b2, . . . bn−1), and errorcorrection codes, being added for executing the error correction uponthe identification information bits when the error(s) occurs/occurtherein, i.e., of m bits (bn, bn+1, bn+2 . . . bn+m−1), including suchthe data hiding and/or water mark or the like therein, thereby formingan additional information data, i.e., of n+m bits (b0, b1, b2 . . . bn,bn+1, . . . bn+m−1) to be embedded into an original data, including suchas text data or audio/video data. In order to reduce influences upon theadditional data due to a transmission system, the same data are embeddedrepetitively, i.e., by a plurality of times (for instance, P times) intothe original data to be transmitted.

[0078] Here, as one way of repetition for each of the information bitsof the additional information data is, each bit is embedded andtransferred by P times, respectively, as is shown below: b0, b0, b0...b0P times b1, b1, b1...b1 P times ... ... ... ... bn+m−1, bn+m−1,bn+m−1...bn+m−1 P times

[0079] or, alternatively, by forming an unit of data of m+n bits withthe additional data to be embedded and transferred, as is shown below:(b0, b1, b2 . . . bn+m−1), (b0, b1, b2 . . . bn+m−1), . . . P timesHowever, other ways than the mentioned in the above can also be appliedthereto. The details in a method for embedding of the additionalinformation data will be given later.

[0080] Heretofore is the explanation on processes or operations at adata transmission side. Namely, the additional information data,including such the identification bits and the error correction code,are embedded or concealed into the transmission data to be transferred,repetitively, and is transferred through the transmission system to areceiver side of the data. At the receiver side, a decision is made onthe basis of so-called a majority rule with respect to the additionalinformation data which are transferred repetitively. For instance, whenthe data bit bO is transferred by P times, the value of the bit isdecided to be that of the majority among b0s of number P, for instance,b0=1 or 0. In the same manner, by collecting data of the P pieces foreach of the bits (b0, b1, b2 . . . bn+m−1) and determining the value foreach bit by the majority rule, the additional information data (of n+mbits) can be obtained. Thereafter, error(s) occurring among theidentification information bits is/are detected and corrected by meansof the error correction codes of m bits, thereby obtaining theidentification information bits of n bits correctly.

[0081] By transferring the additional information data with use of suchthe method, it is possible to practice the error correction by means ofthe error correction code while reducing the error rate in theadditional information data which are embedded and transferred.

[0082]FIG. 2 shows in more details of the processes of the transmissionof the additional information data as shown in FIG. 1. In this exampleshows here, the additional information data are embedded or concealedwithin the video data so as to be transferred. However, the originaldata into which the additional information data are to be embeddedshould not be restricted only to such the specific one, such as thevideo and/or audio data or the like.

[0083] In the same figure, the additional information data are preparedfor the repetitive transmissions of P times with adding the errorcorrection codes to the identification information data, and those areembedded or concealed into the video data. Here, however, points orpositions where the each additional information data is embedded aredetermined in advance, or the information of those points are alsopossible to be already transferred to the receiver side by an anothermeans in advance. The data of image located corresponding to thosepoints where the each additional information data are embedded areconverted or altered in each value of the bits thereof, according to thevalues of the information, though details of the conversion of the bitswill be given later.

[0084] Those embedded additional information data are compressed in themanner which is same to that of the data of the other data, i.e., thedata of pixel blocks of the video data, and are encoded if necessary.The data which are processed in this manner are transferred by recordingthem onto a package medium of such as a CD or a DVD, or are transferreddirectly through radio waves, in such a case of broadcasting.

[0085] Next, the package medium is received and/or reproduced (playback)by means of a reproducing apparatus as a means for receiving, or theradio wave is received by a receiver in the case of the broadcasting.And, then the data are processed with decoding process in accordancewith the encoding method mentioned above. After that, the data which arecompressed are extracted or extended. Here, the embedded additionalinformation data are detected from the pixel data of the pixel blocks ofthe video data by means of a detector for detecting the additionalinformation data which are embedded into the video data. The embeddedadditional information data which can be obtained in this manner aredetected from the positions of the number P, i.e., the P pixel blockswithin the video data, for each of the bits of the additionalinformation data, and the decision by the majority rule is applied withrespect to the each bit. Namely, this process is applied to the n+m bitsso as to obtain the additional information data, and the correction ofthe errors is performed by means of the correction codes also containedin the additional information data, thereby, obtaining the correctvalues of the information bits of the additional information datawithout errors.

[0086] With using such the method, it is possible to transfer theadditional information bits embedded or concealed into the originaldata, as well as to obtain the information bits thereof with a low errorrate, thereby, it is possible to transfer such the addition informationwith a high reliability.

[0087]FIG. 3 shows an embodiment of a process for embedding theadditional information into the video data. A piece of a picture (i.e.,the video data) can be replaced with a set of data, and in order toperform the embedding process to the data, first of all, they aredivided into the plurality of pixel blocks of a squire shape in thenumber 8×8=64, for example. Here, each pixel of them is formed with thedata of a predetermined number of bits, for instance, if it is formedwith the data of 8 bits, it is for a resolution power of 256 steps. And,such the data of the number of sixty-four (64) gathering togetherconstruct each of the pixel blocks.

[0088] Here, in case that a certain pixel block is coincident with thepoint where the additional information data is to be embedded, a processis applied to the pixel block depending on the values, i.e., 1 or 0 ofrespective bits of the additional information data. For example, whenone of the bits of the additional information data which is to beembedded into that point is “1”, then the values of the data of the 64pixels are converted or altered in such a manner that the total value ofthe 64 pixel data comes to be a multiple of 256:

(a 0+a 1+a 2+. . . a 63) mod 256=0 (“mod” indicates a residuum ofdivision)

[0089] on the other hand, when it is “0”, the values of the data a0through a63 are converted or altered in such a manner that the totalvalue of the 64 pixel data comes to be a multiple of 256 plus theresiduum 128, i.e.:

(a 0+a 1+a 2+. . . a 63) mod 256=128

[0090] Here, according to the present invention, the value of the 256(and also 0, and 128) should not be restricted only to that value,however, if it is selected to be a larger one, though it is easy to makethe decision as well as to reduce the number of errors, while theoriginal data of the 64 pixels are changed by large amounts of valuesthereof.

[0091] The values of the 64 pixel data in the one pixel block areconverted or altered in this method, thereby the additional informationdata are embedded into the video data one by one, separately.

[0092] Those additional information data, however, sometimes happen tobe reproduced incorrectly, i.e., with error through the transmissionsystem, in particular when they are compressed/decompressed after beingembedded. Therefore, taking such the case into the consideration, thecondition for deciding the value of the each bit of the additionalinformation data after being received should not be restricted only tothat defined in the above, i.e.,

(a 0+a 1+a 2+. . . a 63) mod 256=0

[0093] however, it is preferable to be selected to 0±α (α is anarbitrary value being equal or less than 64 (α≦64) which is determinedby the compression method, etc.).

[0094] Here is described the example in which the additional informationdata are embedded into the values of the pixel block of the picture of,such as the video data, however, it is also possible to embed or concealthe additional information data into a transmission data, such as valuesof bit-stream which are obtained through a frequency conversion, such asDCT (discrete cosine transfer) or FFT (fast Fourier transform).

[0095]FIG. 4 shows an example of the points or positions, at which theadditional information data are embedded, within one piece of thepicture (an unit of the video data) as a whole. At the plurality ofpoints of number (n+m)×P in the picture data, the additional informationdata are embedded or concealed, separately and repetitively.

[0096] When receiving, the P bits of b0 are gathered from the pointswhere the b0 bits are embedded so as to make the decision on the valueof the b0 bit by the majority rule. This is effected with respect to then+m bits, thereby obtaining the additional information data after themajority rule decision. In this manner, by embedding each bit of theadditional information data into the plurality of points repetitively,it is possible to make the majority rule decision when receiving,thereby enabling reproduction of the additional information bitscorrectly.

[0097]FIG. 5 shows an embodiment of a signal processing apparatus ofperforming the process of coding/decoding, for the data transmissionaccording to the present invention. In this embodiment, there is shown acase where the additional information of several ten bits are embeddedor concealed into the video data and are recorded and/or reproducedinto/from a disc, such as the DVD.

[0098] Here, a reference numeral 1 indicates an input terminal of theidentification information bits, 2 an error correction code generator, 3a repetitive data generator, 4 an input terminal of the video data, 5 apixel block divider, 6 a pixel data generator, 7 an embedding device ofthe additional information data, 8 a compressor/encoder, 9 arecord/playback changeover switch, 10 a pick-up, 11 a disc, 12 a spindlemotor, 13 an extender/decoder, 14 an embedded data detector fordetecting the data being embedded into the data, such as the video data,15 a majority rule decision device, 16 an error correction device, 17 asystem controller, 18 a playback output controller, and 19 an outputterminal of the reproduced video data, respectively.

[0099] In the same figure, the identification information data which isprovided at the input terminal 1 includes, for example, a copy controlinformation which is necessary for playback. Namely, playback control,i.e., inhibit of playback and/or inhibit of outputting the reproducedsignal, is conducted in accordance with this information. The errorcorrection code generator 2 generates and adds so-called parities to theidentification information data at the input terminal 1 as the errorcorrection codes, and the repetitive data generator 3 makes copies ofthe data being formed by adding the error correction codes to theidentification information, for the number of times (i.e., P times) ofbeing transmitted repetitively. The video data at the input terminal 4is an original data of such as the video data, and are coded with apredetermined format so as to be transferred. The pixel block divider 5divides the original video data into the plurality of pixel blocks beingmade of the 8×8 pixel data so as to be embedded with the additionalinformation data therein. The embedding device 7 performs a process forembedding the additional information data, to which the error correctioncodes are added, into the divided pixel blocks of video data. This isdone by embedding one (1) bit of the additional information data at thepredetermined points or positions one by one, repetitively.

[0100] The data formed in this manner are compressed by thecompressor/encoder 8 and then encoded in accordance with a predeterminedrecording format. With this, the data being fitted for the recordingformat are produced and are written by the pickup 10 on a recordinglayer on the disc 11.

[0101] The spindle motor 12 is an electric motor which ratably drivesthe disc 11 therewith.

[0102] When performing playback (reproducing), the record/playbackchange-over switch 9 is turned to the playback side, and the reproduceddata are sent from the pickup 10 which reads out the signals recorded onthe disc 11 to the extender/decoder 13. With this extender/decoder 13, adecoding process in accordance with the coding method is performed onthe reproduced data, and then the data are extended. From the data, inparticular, from the pixel blocks in which the additional informationdata are embedded, the additional information data of the number ofrepetition (i.e., P times) are detected with the embedded data detector14. The majority rule decision device 15 makes decisions on the value ofeach bit of additional information data which are detected at the numberof the repetition number (i.e., P times), and the additional informationdata are constructed with the data which are decided by the majorityrule. The error correction device 16 detects the error(s) in theinformation bits of the identification data and corrects it/them, withuse of the correction codes which are contained in the embeddedadditional information data. The information bits which are reproducedin this manner has a low possibility of error. And, if the reproducedinformation bits construct the identification data including the copycontrol, such as the information of inhibiting or protecting from thecopy thereof, then the system controller 17 controls the playback outputcontroller 18 in such a manner that it stops outputting of thereproduced video data at the output terminal 19.

[0103] Here, it is assumed that the each additional information data isconstructed with the total 46 bits data, i.e., with the identificationdata of 32 bits, which are provided at the input terminal 1, the errorcorrection code of 6 bits, and 8 bits data indicting a head of the data.If 2,000 points or positions are set as those for embedding theadditional information data therein, within one piece of the pictures,then the additional information data can be transferred by 43 times,repeatedly. Here, if the error rate in the transmission system is 0.1,then the probability that the error can be contained in the informationbits comes to be 1×10E⁻¹¹ after being conducted with the majority ruledecisions thereon in the playback operation. If the error rate in thetransmission system is 0.2, then it comes to be about 5×10E⁻⁶. With suchthe error rate, in case where the error correction is executed with useof the error correction codes of 6 bits, the error rate comes down to1×10E⁻⁹˜1×10E⁻¹⁰, therefore it is possible to suppress an input errorrate down to low.

[0104]FIG. 6 shows an another variation of the flow of processes ofcoding/decoding for the data transfer, according to the presentinvention. Here, the reference numerals same to those in FIG. 1 indicatethe same elements thereof.

[0105] In FIG. 6, as in the same manner as shown in FIG. 1, theidentification information data of n bits to be transferred are encodedor converted into the additional information data of n+m bits by using aconversion table which is provided for encoding of the identificationdata in accordance with a predetermined rule. The same additionalinformation data encoded are also transferred repetitively at theplurality of times (P times) for lessening the influence upon occurrenceof the change or error in the additional information data due to thecondition of the transmission system. Here, by transferring the numberof repetition P in advance with use of a separate means, it is possibleto set the repetition number corresponding to the condition of thetransmission system suitably, even in a case where there are pluralkinds of transmission systems, in which the they are different from oneother in the most suitable number for the repetition. In the case wherethe transmission system is the disc, for example, the repetition numberis determined from the data compression/extension rate in the playbackoperation as well as the error rate of the disc, and the value of it isstored or recorded in a specific portion of the disc, i.e., a TOC (Tableof Contents) area, for example. And, when reproducing, the repetitionnumber is reproduced first of all. With use of such the method, it ispossible to transfer the additional information data with the repetitionnumber being suitable for the transmission system.

[0106] For instance, in a case where the data compression, such as MPEGor the like, is applied to the video data for the transmission thereof,since there is provided a header for each unit, i.e., a picture of thescreen in the data format of the MPEG, it is possible to insert therepetition number P into a portion of the header as an additionalinformation thereto. Further, it is also possible to insert therepetition number P for each of an unit of GOP (Group of Picture), whichis a data unit in the MPEG format. In those cases, the repetition numberP can be transferred by the unit of the picture or the GOP, therebyenabling the repetition which is most suitable for the video data.

[0107] Here, if the value of the repetition number P can be deciphered,there is a possibility that it is changed or altered in the valuethereof. For keeping a secrecy thereof, it is preferable that therepetition number P is stored or written in code, thereby making itdifficult to be deciphered, and strengthening an algorithm of it.

[0108] Transferring the information data with use of such the methodmentioned above, it is possible to set the repetition number P suitablycorresponding to the condition of the transmission system, even in acase where there are plural kinds of transmission systems in which thethey are different from one other in the most suitable number for therepetition. Thereby, it is possible to execute the majority ruledecision on the additional information data so as to reduce down theerror rate thereof, and to enable the error correction with use of theerror correction codes. Further, with the method being same to this, itis also possible to transfer the information relating to the positionsor points in which the additional information data are embedded and/orthe threshold value (such as the α=256 mentioned in the above) forexecuting the majority rule decision. Moreover, though the explanationwas given on the majority rule decision which is used for deciding thevalue of each bit of the additional information data from the P numberof embedded data in the embodiments mentioned in the above, however, thepresent invention should not be restricted only to such the rule.Namely, in place of the majority rule decision, a way of decision ofusing a threshold value is also applicable, i.e., if the same value (1or 0) is detected by a plurality of times which is greater than thethreshold value thereof, for each one bit of the additional informationdata, then the detected value is decided to be the value of that bit.

[0109]FIG. 7 also shows a further other variation of the flow ofprocesses of encoding/decoding for the data transfer, according to thepresent invention. Here, the reference numerals same to those in FIG. 1indicate the same elements thereof.

[0110] In FIG. 7, also in the same manner as shown in FIG. 1, theidentification information data of n bits to be transferred are encodedinto the additional information data of n+m bits by a conversion tablewhich is provided for converting the identification information data inaccordance with a predetermined rule. In this time, it is preferable toencode or alter the data into those which are not easily confused withthe other data. The additional information data encoded are alsotransferred repetitively at a plurality of times (P times) for lesseningthe influence upon occurrence of the change or error in the additionalinformation data due to the condition of the transmission system.Heretofore is the description about the transmitter side. The additionalinformation data are transmitted repeatedly are transferred to thereceiving side. At the receiver side, with respect to the additionalinformation data which are transmitted repeatedly, the decisions aremade by the majority rule by the number of repetitions, i.e., P times.Namely, if the data is the digital data, the value which are detected bytimes more than P/2 is decided to be the value of the data. Thismajority rule decision is made by P times with respect to each bit ofthe data of n+m bits, thereby obtaining the additional information dataof n+m bits. After that, the additional information data is decodedthrough a decoder table which is contrary to that of the encoder usedwhen encoding the data, thereby obtaining the original identificationinformation data of the n bits.

[0111] Transferring the information data with use of such the methodmentioned above, it is possible to execute the majority rule decisionupon the additional information data so as to reduce down the error ratethereof, and to enable the error correction with use of the errorcorrection codes, even in case where the error rate of the data is highdepending on the transmission system, therefore is impossible the errorcorrection with use of the error correction codes.

[0112] Further, FIG. 8 shows an another embodiment of the flow ofprocesses of coding/decoding for the data transfer, according to thepresent invention.

[0113] In FIG. 8, each of the additional information data is alsoembedded into the units of the pixel block, in the same manner as isdisclosed in FIG. 3 above. In this embodiment, it is assumed that thenumber of the bits of the identification information data to betransferred is constructed with K bits (for example, K=6, therefore,2⁶=64 patterns), and that the number of the pixel blocks into which theinformation bits of the identification information data are embedded isL within each one piece of the pictures. In this embodiment, forinstance, if the bits of the identification information data are“00⁻0000”, the total value (=0) of the bits of the identificationinformation data is embedded into every L pieces of the pixel blocks ofthe one piece of the picture, which are indicated by “” in the figure,and if the bits of the identification information data are “00⁻0001”,the total value (=1) of the of the identification information data isembedded into the every L pieces of the pixel blocks of the one piece ofthe picture, which are indicated by “▪” in the figure. In this manner,the identification information data are embedded into the each picture,corresponding to the 64 kinds of patterns in case that it is of six (6)bits data, in such a manner that the position of the every pixel blocknever overlapped among all of the 64 kinds of patterns of the picturesinto which the identification information data are embedded. Here, atleast K×L (64×60=3840) pixel blocks are necessary to be contained in onepiece of the picture. This is because, if the number is less than that,the embedding patterns overlap to each other, therefore, the probabilityof detecting the embedded identification information data incorrectlywith error(s) is increased, when deciding the corresponding bits ofthem.

[0114] Embedding the identification information data in this manner,while it is possible to decide if the identification data is embedded ornot, upon the presence of data corresponding to the specific embeddedpatterns in the information data of the reproduced data at the receiverside. And, also it is possible to decide the identification informationdata upon a fact that which embedded pattern it is coincide with or nearto. In case that the identification information data are transferred inthis method, there can be happen a case where the embedded position(s)is/are detected at the position(s) other than those of the embeddedpattern mentioned above, however, by searching or checking it over thepatterns at the positions of the number L, since only one pattern comesto be approximated to, thereby it is possible to decide theidentification information uniquely.

[0115] Further, as the embedded patterns can be used those which arepredetermined previously, however, it is also possible to code theinformation relating to the embedded pattern corresponding to eachidentification information bit so as to transfer them as data inadvance, thereby using the embedded patterns corresponding to therespective conditions of the transmission systems of the data,appropriately.

[0116]FIG. 9 shows an example of a method of deciding the identificationinformation data when receiving them which are embedded in accordancewith the manner shown in FIG. 8. Further, FIG. 10 shows an example ofchanges in the condition of the decisions on the identificationinformation data at that time.

[0117] In FIG. 9, first of all, it is decided whether the identificationinformation data are embedded or not, upon the presence of the datawhich is near to one of the patters of the identification informationdata in the received data, and it is decided by a fact which one of theembedded patterns it is coincide with. Here, when embedding theidentification information data, the value to be altered or converted isdetermined within a certain range of a value, for example, when thetotal value of the values of the pixel data of the pattern of theidentification information bit is changed within a range 512±64 (forinstance, in case of data of 9 bits), the embedding of the data can bedetected at a probability of one fourth (¼) of a value in a case wherethe identification information data are embedded, even when noidentification information data are embedded. Therefore, which one ofthe embedded patterns the data comes to be coincident with can bedecided, though they are not completely coincident with due to theerror(s) of the transmission system, by selecting one among of them, inparticular, which shows more points coincident with those of the patternthan the others.

[0118] Here, assuming that one piece of the picture is to be the data ofone frame, the data of the embedded pattern corresponding to theidentification information bits are converted into the data of the oneframe to be transferred. At this time, if the probability of the errordetection in the identification information bits is high as the resultof transmission thereof, it is possible to increase up the reliabilityby detecting and deciding the identification information bits in asequence. For example, it is conditioned that the identificationinformation bits can be detected by detecting them for 4 frames insequence, continuously, and that the detection is started again if aframe which does not coincide with is detected on the way of detectiontherefore the identification information bits cannot be detected for 4frames continuously. And as the result of this, when the sameidentification bits are detected continuously, the identification bitscan be decided.

[0119] Reference marks {circle over (1)} through {circle over (6)} inFIG. 10 correspond to branches of the flow shown in FIG. 9. Whendetecting the frames in which the identification information data areembedded, it comes to the branch {circle over (2)}, while it comes tothe branch {circle over (1)} when no such the frame in which theidentification information data are embedded can be detected. And, whenfour (4) of such the frames can be detected continuously, it comes tothe branch {circle over (4)}, while it comes to the branch {circle over(3)} when no such the continuous frames cannot be found, therebydetermining the information bits thereof.

[0120] Next, in FIG. 9, after determining the identification informationbits once, they will not be invalidated soon, even if occurring such theframe that it is not coincide with the embedding pattern therefore theidentification information bits cannot be determined therefrom. Forinstance, the identification information bits being determined once arecanceled only when the same identification information bits can bedetected continuously for the four (4) frames in sequence, therebytrying the determination again. In this way, by protecting theidentification information bits being determined once, it is possible tomaintain them dealing with omission of data due to deterioration of theerror rate in the transmission system.

[0121] In FIG. 10, when no frames cannot be found continuously four (4)times, the flow comes to the branch {circle over (6)}, however, if notso, it comes to the branch {circle over (5)} so as to maintain theidentification information bits as before.

[0122] With use of such the method, it is possible to prevent from theerroneous detection of the identification information bits, and also toobtain the protection of them after the detection thereof.

[0123] As is fully described in the above, according to the presentinvention, when transmitting the video and/or audio data added with theadditional information bits of such as the copy protection, the errorcorrection codes are added to the additional information bits so as tocorrect them if error occurs therein, thereby preparing the additionalinformation data to be transmitted. And, for lessening the influenceupon the additional information data due to the change or error of thedata in the transmission system, the same additional information dataare embedded into the original video data repetitively, by plural times(i.e., P times).

[0124] When receiving, with respect to the additional information datawhich are embedded repetitively, the determination by the majority ruleis executed thereon. Assuming that the additional information data arerepeated by P times, a value of the majority (more than P/2) among thereceived data of number P is decided to be the value. The determinationby the majority rule is executed by gathering the data of the number Pfor all of the bits, thereby obtaining the additional information data.After that, the errors of the additional information bits are detectedand/or corrected by use of the error correction codes, thereby obtainingthe identification information bits contained therein, correctly.

[0125] By transmitting the information data with use of such the method,the error rate of the additional information data can be reduced throughthe determination by the majority rule, and correction of error can beperformed by use of the error correction codes, even in the case wherethe error correction cannot be executed because of high error rate ofthe data due to the transmission system, thereby achieving thetransmission of such the additional information data with highreliability.

[0126] Further, by determining the embedding patterns corresponding theadditional information bits and embedding them with converting orchanging the data values of the pixel blocks thereof, while determiningthe additional information bits on the basis of continuous detection ofthe embedding patters when receiving, and resetting the additionalinformation bits (i.e., deciding that no additional information bits areembedded) when occurring such the condition that no embedded patterncannot detected continuously, after once making the determinationthereof, thereby the determination and the protection of the additionalinformation bits can be achieved.

What is claimed is:
 1. A data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: a fist step for adding error correction codes for correcting error to said additional information data; a second step for embedding said additional information data added with said error correction codes into the information data by plural times, repetitively; and a third step for transmitting the information data embedded with the repetitive additional information data therein.
 2. A data transmission method for the information data transmitted through the method as claimed in claim 1, comprising, at a receiver side, following steps: a fourth step for receiving the transmitted information data embedded with the repetitive additional information data therein; a fifth step for detecting the repetitive additional information data embedded from said transmitted information data received in the fourth step; a sixth step for determining said additional information data on a basis of a majority rule when receiving said information data; and a seventh step for correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.
 3. A data transmission method as claimed in claim 1 or 2, wherein said information data includes at least one of video data, audio data and text data.
 4. A data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: a fist step for encoding said additional information data in accordance with a predetermined conversion table; a second step for embedding said additional information data encoded in the above step into the information data by plural times, repetitively; and a third step for transmitting the information data embedded with the repetitive additional encoded data therein.
 5. A data transmission method for the information data transmitted through the method as claimed in claim 4, comprising, at a receiver side, following steps: a fourth step for receiving the transmitted information data embedded with the repetitive additional information data encoded; a fifth step for detecting the repetitive additional information data encoded, which are embedded within the information data received; a sixth step for determining said encoded additional information data on a basis of a majority rule of the repetitive encoded additional information data detected; and a seventh step for decoding the encoded data into the additional information data.
 6. A data transmission method as claimed in claim 4 or 5, wherein said information data includes at least one of video data, audio data and text data.
 7. A data transmission method for information data containing additional information data therewith, comprising, at a transmitter side, following steps: a step for preparing data frames of said information data into which the additional information data are to be embedded; a step for altering at least part of the data frame in accordance with predetermined patterns corresponding to the additional information data to be embedded, for the plural continuous frames, repetitively; and a step for transmitting the information data embedded with the repetitive additional information data therein.
 8. A data transmission method for the information data transmitted through the method as claimed in claim 7, comprising, at a receiver side, following steps: a step for receiving the transmitted information data embedded with the repetitive additional information data therein; a step for detecting the repetitive additional information data embedded from said transmitted information data; and a step for determining said additional information data on a basis of continuity of the repetitive additional information data detected for a predetermined times.
 9. A data transmission method as claimed in claim 7 or 8, wherein said information data includes at least one of video data, audio data and text data.
 10. A data transmitting apparatus for transmitting information data containing additional information data therewith, comprising: a first means for adding error correction codes for correcting error to said additional information data; a second means for embedding the additional information data added with the error correction codes by said first means into the information data by plural times, repetitively; and a third means for transmitting the information data embedded with the repetitive additional information data therein.
 11. A data transmitting apparatus as claimed in claim 10, wherein said third means includes means for recording the information data embedded with the repetitive additional information data onto an optical information recording medium.
 12. A data reproducing apparatus for reproducing the transmitted information data transmitted by the data transmitting apparatus defined in claim 10, comprising: a first means for receiving the transmitted information data embedded with the repetitive additional information data therein; a second means for detecting the additional information data embedded from the transmitted information data received by said first means; a third means for determining said additional information data on a basis of a majority rule when receiving said information data; and a fourth means for correcting error with using the error correction codes received and determined when said additional information data contains error(s) therein.
 13. A data transmitting apparatus for transmitting information data containing additional information data therewith, comprising: a fist means for encoding said additional information data in accordance with a predetermined conversion table; a second means for embedding said additional information data encoded in the first means into the information data by plural times, repetitively; and a third means for transmitting the information data embedded with the repetitive additional encoded data therein.
 14. A data transmitting apparatus as claimed in claim 13, wherein said third means includes means for recording the information data embedded with the repetitive additional information data onto an optical information recording medium.
 15. A data reproducing apparatus for reproducing the transmitted information data transmitted by the data transmitting apparatus defined in claim 13, comprising: a first means for receiving the transmitted information data embedded with the repetitive additional information data encoded; a second means for detecting the repetitive additional information data encoded which are embedded within the information data received; a third means for determining said encoded additional information data on a basis of a majority rule of the repetitive encoded additional information data detected; and a fourth means for decoding the encoded data into the additional information data.
 16. A data transmitting apparatus for transmitting information data containing additional information data therewith, comprising: a first means for preparing data frames of said information data into which the additional information data are embedded; a second means for altering at least part of the data frame in accordance with predetermined patterns corresponding to additional information data to be embedded, for the plural continuous frames, repetitively; and a third means for transmitting the information data embedded with the repetitive additional information data therein.
 17. A data transmitting apparatus as claimed in claim 16, wherein said third means includes means for recording the information data embedded with the repetitive additional information data onto an optical information recording medium.
 18. A data reproducing apparatus for reproducing the transmitted information data transmitted by the data transmitting apparatus defined in claim 16, comprising: a first means for receiving the transmitted information data embedded with the repetitive additional information data therein; a second means for detecting the repetitive additional information data embedded from said transmitted information data; and a third means for determining said additional information data on a basis of continuity of the repetitive additional data detected for a predetermined times.
 19. An information recording medium for recording data therein, comprising: information data being reproducible; additional information data which are embedded into said information data repetitively; and error correction codes which are added to said additional information data and also embedded into said information data repetitively.
 20. An information recording medium as claimed in claim 19, wherein an information, relating to a repetition number of the additional information data embedded into said information data, is recorded into a part of said information recording medium. 